REPORT OF THE BUREAU OF ANIMAL INDUSTRY. 115 



SUGGESTIONS AS TO THE MEANS OF PREVENTING THE SPREAD OF 



SWINE PLAGUE. 



Experiments with, the microbe of this disease have shown that it 

 has very feeble powers of resistance to external agencies. It is killed 

 by drying within twenty-four to forty-eight hours, and it is speedily 

 destroyed in water. Its life in the soil is no doubt very limited for 

 these reasons. Moreover, it fails to multiply on vegetable substrata, 

 like potato, and grows feebly in most nutritive media. In these re- 

 spects it differs very markedly from the hog cholera germ, which 

 manifests a very decided resistance to the destructive agencies in 

 water and soil. 



It seems probable that infectious matter from swine plague is more 

 directly conveyed from one animal to another than is the case with 

 hog cholera virus. Direct contact of the sick with the healthy must 

 be considered as one of the principal means of infection. The mucus 

 from the lungs contains the disease germs in abundance, and a forci- 

 ble expiration by which particles of water, etc., are ejected from the 

 nostrils to some distance may easily communicate the disease to 

 another. The soil at the same time becomes infected from intestinal 

 discharges, as with hog cholera, and it is therefore necessary to sep- 

 arate the well from the sick by removing them to uninfected grounds; 

 but the infection of the soil and pens can not live for more than two 

 weeks, and in a month such places may be considered safe. 



The same remarks apply to both diseases as regards disinfection. 

 This need not be so thorough in swine plague if the pens or grounds 

 are left unused for a month, and if the healthy be kept away from 

 the sick. At any rate, disinfection should always be practiced if 

 possible. For this purpose lime is perhaps the best and cheapest, 

 and for suggestions as to its use the reader is referred to another part 

 of this report. 



There may be some difficulty in determining which disease has 

 attacked a given herd, or whether both are not actually present. 

 Very severe lung disease is now the only sign that is of any positive 

 value in the detection of swine plague, unless it be bacteriological 

 testimony, which is the safest, but not at hand under most circum- 

 stances. Where any doubt exists the disease should be treated as 

 hog cholera, and all the rules for disinfection and isolation which 

 have been suggested in this and the preceding report for that disease 

 should be followed out. In the disinfection lime should take the 

 place of the mercuric chloride recommended in the report for 1886. 



Whether this disease can be prevented by inoculation requires 

 more evidence than has been obtained ttris far, and experiments to 

 test this matter are now going on. 



